372
FXUS61 KBUF 021857
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
257 PM EDT Tue Jul 2 2024

.SYNOPSIS...
High pressure will move off into New England today while maintaining
fair dry weather. A deepening southerly flow between the exiting
high pressure and an approaching cold front will then allow mid
summer heat and humidity to return on Wednesday. Showers and
thunderstorms...many with drenching downpours will then make their
way into our region later Wednesday and Wednesday evening.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Fair dry weather again today with surface high pressure over NY
State. There will be some high clouds due to a decaying upstream MCS
this afternoon. Highs will be found in the mid/upper 70s across the
higher terrain to low 80s elsewhere.

A warm front will enter the area tonight and may produce a sprinkle
or isolated shower. Although...it is very likely that we will only
see an increase in mid to high clouds as was mentioned. Very low
PoPs (< 20%) considering Bufkit profiles do show a very prominent dry
layer between 5K and 10k feet.

Otherwise...not quite as cool with lows generally in the 60s. A few
reading may dip into the 50s...this would be for locales well inland
east of Lake Ontario (Lewis Co).

Wednesday is then GUARANTEED to be very warm and moderately humid...
as a deepening southerly flow increases ahead of an approaching cold
front. This will prompt Tds to return to the mid and upper
60s...while PWAT values will surge to around 2 inches. As is most
often the case during the summer...the approaching cold front will
be preceded by a pre-frontal sfc trough. This will help to initiate
some thunderstorms over the Southern Tier and western Finger Lakes
during the afternoon...then more widespread convection can be
expected late in the day into the evening with the cold front.
Forecast bulk shear of 40kts or so will increase the risk for
organized convection that could produce gusty winds...particularly
over southern areas. SPC highlights the most favored area for severe
weather to be well to our southwest...in the vcnty of the Ohio
valley.

Temperatures on Wednesday will top out between the 85F to 90F range
...with the higher end of that range expected for the lake plains
where heat index values will approach the mid 90s.

Wednesday night...showers and storms will dwindle as the cold front
settles south of the Lower Lakes overnight. Otherwise...not overly
cool behind this front with lows generally found in the 60s.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
Weak cold frontal boundary will continue to press southeast through
the region Thursday. A few showers or a thunderstorm will be
possible closer to the New York/Pennsylvania state line, especially
if the front slows down and does not clear the area by afternoon.
Otherwise drier air advecting in behind the front will keep the
remainder of the area dry. Not much of a push of cooler air
behind the front, so temperatures Thursday still will be warm
with highs mostly in the lower to mid 80s, but humidity levels
should slowly drop off through the day.

Dry conditions should continue Thursday night with the boundary
to our south, although the boundary will start to makes its way
northward as a warm front with at least some small risk for
some convection working back into the Southern Tier late
Thursday night.

Warm frontal boundary will continue to make its way northward
through the region Friday with temperatures following suit with
highs in the mid to upper 80s, with the warmest heat index
values approaching 90F. With the very warm and humid air mass
in place, a few showers and thunderstorms may develop, mainly
across western New York.

A better convective signal exists for the Friday night period,
anchored by the arrival of organized forced ascent associated
with a mid level wave shortwave tracking eastward from the upper
Midwest into the Great Lakes.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
The low pressure system that brought widespread showers Friday night
will become vertically stacked across the upper Great Lakes by
Saturday morning, causing it to weaken as it tracks northeast into
Quebec. The system`s cold front will be in the process of marching
east through western NY Saturday morning, with a mid/upper level dry
slot following in its immediate wake. While showers and possibly a
few thunderstorms should be ongoing Saturday morning across the
North Country Saturday ahead of the front, confidence is lower in
whether or not the dry slot will extend far enough north to bring a
period of drier weather to our eastern zones by the afternoon. Have
therefore undercut NBM PoPs by a small amount across WNY in the
morning to better indicate the expected dry interlude, before
additional synoptic moisture out ahead of the main trough axis
combines with diurnal heating in the afternoon to increase
shower/thunderstorm chances. While temperatures Saturday will likely
depend on the exact timing of the front in the morning, highs are
expected to generally range from the upper 70s to the mid 80s,
warmest across the Finger Lakes region and in the Genesee Valley.

The mid-level trough axis and moisture starved secondary cold front
will swing through the region Saturday night. An area of high
pressure subsidence building in its wake will lead to sharply
decreasing chances for showers and thunderstorms from west to east
overnight, with just a low-end chance lingering across the North
Country by Sunday morning. Lows Saturday night will range in the 60s
with lower overall humidity.

Surface high pressure centered to our south along with a flattening
mid-level ridge moving through the Great Lakes will then crest over
our region through Sunday night, ensuring fair dry weather to cap
off the weekend. Highs Sunday will be comfortable in the 70s to low
80s, with lows Sunday night in the low to mid 60s.

Unsettled weather returns for the work week as weak high pressure is
gradually replaced by yet another broad, weakening trough across the
Great Lakes. While Monday is expected to be mainly dry as the
eastern Great Lakes looks to be sandwiched between areas of deeper
moisture to our west and along the East Coast, some diurnal shower
activity can`t be completely ruled out. The next large scale system
will come sometime Monday night into Tuesday as a shortwave trough
moves out of the Ohio Valley, partially phasing with the longwave
trough over the Great Lakes as it moves into the forecast area.
Could see PoPs being raised into lkly territory for parts of the
area with subsequent updates as timing discrepancies are better
refined, but at this range will stick to Chc. Otherwise, the
position of the high to the east should give temps a solid boost
Monday back into the mid and upper 80s across the Lake Plains,
cooling off again slightly for Tuesday.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
High pressure will produce VFR through the entire area today.

Tonight...a warm front will work through the area overnight. It
might bring with it a sprinkle or shower but VFR is expected to be
maintain.

Outlook...

Wednesday...VFR, then MVFR with showers and thunderstorms late
Wednesday afternoon and Wednesday night.
Thursday...Mainly VFR with a low chance of a shower or thunderstorm
across the western Southern Tier.
Friday and Saturday... Mainly VFR with a chance of showers and
thunderstorms.
Sunday...VFR

&&

.MARINE...
High pressure will bring light winds and minimal wave action thorugh
this evening.

High pressure exits tonight and a warm front will work across the
lakes overnight. Winds will pickup late out of the south pushing
higher wave action off shore as we move into Wednesday.

A cold front will approach the region Wednesday. Winds will veer to
the southwest ahead of the cold front.  While fair weather will
remain in place through at least midday...there will be an
increasing risk for thunderstorms in the afternoon and evening.

In the wake of the cold front...fair weather will return to the
region later Wednesday night with subsiding southwest breezes.

Looking ahead to the Fourth of July...gentle to moderate winds will
be in place throughout the region. These winds will be from the
southwest on Lake Erie and primarily from the west on Lake Ontario.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...AR/RSH
NEAR TERM...AR/RSH
SHORT TERM...TMA
LONG TERM...PP
AVIATION...AR
MARINE...AR/RSH